Geodatabases, Domains, Attributes

 Introduction:

Planning a collection of data points before entering the field can help properly collect data and allow concise collection of certain aspects. In this lab we discussed the development of geodatabases and its importance as a work space. The Geodatabase can also be a mobile platform that can be used both in lab and in the field by using the ArcPad Feature. This was utilized to collect data for microclimates. The implemanintation of geo databases in the field is important because it allows us to create domains and fields while away from a terminal that has access to ArcGIS or Catalog. This will allow us to be a mobile GIS platform.

The Mobile Platform:

This lab focuses on microclimate data. A micro climate is a climate of a small or restricted area which differs from the surrounding area. A good example of this would be the wind speed is usually higher in a area that funnels the wind in creating a higher wind speed. To map this data we will have to be in the field for mobile collection. In order to collect in the field we have to use the Trimble Juno platform. This platform is useful since it has GPS based collection and can be integrated with Geodatabases that we create in the lab.

Methods:

The first step to getting ready for the field work is to create a Geodatabase in ArcCatolog. In ArcCatalog we created a file Geodatabase which is perferable for single or small work groups and is a cross platform system, which is useful since we will have to import this database to our Juno hand held units later.

After the database is completed we have to create Domains and fields. Domains are created in database and the fields are created in shapefiles. These two items can then be connected in ArcGIS to give attributes to the points that we collected. In ArcCatolog we have to think about what we want our domains to be.  This will help create the rules and legal values of the field type for enforcing data entry. For example we would want to have a short interger in for wind speed. Since the weather is also really nice out we would want to have a range of temperature to be relevenet to our collecting needs. This can be expressed as having a collection range of 20°F to 60°F, anything below or above will be ignored since this would be an error reading. Since we are collecting Microclimate data we will have to think about the what data we will collect. We decided to collect based on humidity, dew point, windspeed, temperature, and wind direction.

We are then ready to edit our domains with our selected data. To edit the domain we will have to right click on the file geodatabase and click properties. This will open the tab which contains the domain tab. We can then create the domain name and description. Also from this area we can select the type of data that can be entered in the field. The examples of this are text data, short interger, long interger or float. The last one is coded values. This can be coded with their own separate descriptions.  Once all our domains are set up we can move to ArcGis to complete the transfer of data.

Once in ArcGis we can begin to transfer the data over to the Trimble Unit. To do this we will have to activate the extension ArcPad Data Manger in the Extensions dropdown menu. We will then hit the button Get Data for ArcPad this will open up a wizard that will walk us through the entire process. Since we have our Geodatabase ready to go we can choose the menu Checkout all Geodtabase layers. This can also include a background image for reference, I howvere could not get a reference image to appear, this step however is purely optional. We can then change the file name of a folder that will store the data that is collected. I selected Micro_Kerraj for my storage area. The ArcPad manager will then create a ArcPad Map (.apm file) this file is what we will be using in the field for collection. Once this project is created we then create a backup folder incase something goes wrong, just to be safe.

To deploy this information on to the Juno unit we then just collect the GPS unit to the computer by using a USB, we will then go into the file system of the Juno and drag and drop the Micro_Kerraj folder that we created. We are now ready to go out and collect micro climate data. When we go out into the field we can see that the micro climate domains that we have created are visible and we have a range that we can follow. This helps the mapping process by allowing us to import a variety of data instantly that can be directly imported back into ArcGis.

Discussion:

Creating the Domains and the fields were easily handled but when I went to import a background image for reference nothing would work, since this step was optional I opted to leave it out of my final project. This however did make collection a bit more difficult since I had no bearing of where I truly was.  Importing a geodatabase to a hand held collection system is a simpler way then just simply going out and collecting points and collecting the data seperatly and combining them together later in ArcGIS. This field method allows for quicker data acquisition.

Conclusion:

GPS data collection with mapping GPS is different than just gathering a point. With the power of having a geodatabase behind the mapping unit we can give our points data instantly so that no additional steps would have to be taken when we import the data back into ArcGIS. This is also important since we will were doing proper data base setup before we left. If we were to accidently input -100°F in the Juno and we did not have the range set up we would have a huge outlier that could potentially skew our data. This is why it is important to have proper database setup and normalization and why this was an important project to learn.